PURPOSE: To increase the activity of a catalyst in the synthesis of hydrocarbon and to improve the durability by spray-drying a mixture of an aq. soln. contg. components to be supported with superfine alumina powder of ≤1μm average particle size and by calcining the resulting dried product.

CONSTITUTION: An aq. soln. contg. components to be supported such as an iron family element, manganese and a platinum family element is mixed with superfine alumina powder of ≤1μm average particle size. The mixture is spray- dried and the resulting dried product is calcined to produce a catalyst for synthesizing hydrocarbon. The dried product is preferably calcined at 450W550°C in the air. The supported components in the catalyst are preferably 10W30wt.% iron family element, manganese in 0.14W1.4 weight ratio to the iron family element and 0.05W2wt.% platinum family element. Cobalt is suitable for use as the iron family element and ruthenium as the platinum family element.